One- and two-dimensional solid-state magic angle spinning NMR studies on the hydration process of layered sodium disilicate SKS-6

Xuanjun Ai; Feng Deng; Jinxiang Dong; Wei Hu; Hong Xu; Chaohui Ye

doi:10.1016/j.ssnmr.2003.10.002

One- and two-dimensional solid-state magic angle spinning NMR studies on the hydration process of layered sodium disilicate SKS-6

Solid State Nucl Magn Reson. 2004 Jun;25(4):216-26. doi: 10.1016/j.ssnmr.2003.10.002.

Authors

Xuanjun Ai¹, Feng Deng, Jinxiang Dong, Wei Hu, Hong Xu, Chaohui Ye

Affiliation

¹ State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, PR China.

PMID: 15028272
DOI: 10.1016/j.ssnmr.2003.10.002

Abstract

Three different kinds of silanols, which include isolated silanol, silanol I (with the hydroxyl proton bonded to an oxygen atom in the adjacent layer) and silanol II (with the hydroxyl proton bonded to the non-bridging oxygen at the same silicon atom), are generated during the hydration process of SKS-6 (delta-Na2Si2O5). 1H-1H nuclear Overhauser enhancement spectroscopy reveals that the proton of silanol I has an effective chemical exchange or spin diffusion with the proton of hydrogen-bonded water, while the proton of silanol II is likely far away from the other proton-containing species. 29Si magic angle spinning, 1H-->29Si CP/MAS NMR and 1H-29Si phase-modulated Lee-Goldburg decoupled correlation experiments demonstrate that the local environments of the silicon sites in the final hydrated sample are mainly composed of Q2 [(SiO)2Si(OH)O(-)Na+], Q3 [(SiO)3Si(OH) and (SiO)3SiO(-)Na+] and Q4 [Si(OSi)4] groups.